/**
 * @brief  ARM_DWT_Delay
 */

#include "arm_dwt.h"

/**
 * @brief  Initializes DWT_Clock_Cycle_Count for DWT_Delay_us function
 * @return Error DWT counter
 *         1: clock cycle counter not started
 *         0: clock cycle counter works
 */
int32_t ARM_DWT_Delay_Init(void) 
{
  /* Disable TRC */
  CoreDebug->DEMCR &= ~CoreDebug_DEMCR_TRCENA_Msk; 	// ~0x01000000;
  /* Enable TRC */
  CoreDebug->DEMCR |= CoreDebug_DEMCR_TRCENA_Msk; 	// 0x01000000;

  /* Disable clock cycle counter */
  DWT->CTRL &= ~DWT_CTRL_CYCCNTENA_Msk; 	// ~0x00000001;
  /* Enable  clock cycle counter */
  DWT->CTRL |=  DWT_CTRL_CYCCNTENA_Msk; 	// 0x00000001;

  /* Reset the clock cycle counter value */
  DWT->CYCCNT = 0;

  /* 3 NO OPERATION instructions */
  __ASM volatile ("NOP");
  __ASM volatile ("NOP");
  __ASM volatile ("NOP");

  /* Check if clock cycle counter has started */
  if (DWT->CYCCNT)
  {
    return 0; /* clock cycle counter started */
  }
  else
  {
    return 1; /* clock cycle counter not started */
  }
}

